This article discusses the history of enzyme kinetics developed by Michaelis and Menten, and recent work extending kinetics for enzyme-catalyzed reactions in organic solvents. Based on kinetic studies of the transesterification of vinyl methacrylate with 2-hydroxyethyl acrylate catalyzed by Candida antarctica lipase B, a new model is proposed that resembles the kinetic model of controlled/living polymerizations governed by dynamic equilibrium of active and dormant species. Experimental data indicates that by judicious selection of reaction conditions steady-state conditions can be achieved and very clean products with quantitative conversion can be produced. (c) 2016 American Institute of Chemical Engineers AIChE J, 63: 266-272, 2017